This invention concerns protection devices for magnetic recording media of the type commonly known as floppy disks or floppy diskettes, and in particular, for those floppy diskettes employing thin jackets, as well as other recorded media.
Contamination from the environment can reduce the performance of floppy diskettes. Such contamination may be the result of airborne particulate matter, such as dust, oil, grease and dirt from human handling, as well as oxide redeposits from the diskettes themselves.
A floppy diskette typically comprises a thin circular disk, one or both sides of which are coated with a magnetic material. The disk has a central opening adjacent to which a disk drive may engage the disk in order to rotate it. The disk is disposed in a thin envelope-like jacket of essentially square construction which has central openings adjacent to the central opening of the disk, but somewhat larger than it in order to permit the disk drive to engage the disk. In addition, the jacket has read-write access openings which permit magnetic heads to engage the information storing portion of the disk to read or write thereon, and/or to allow pressure pads to press against the disk. The jacket of the floppy diskette may be made of a thin stiffened material, such as paper or polyvinyl chloride. Other openings, such as for synchronization purposes may also be provided.
When not in use, floppy diskettes are often stored in envelopes which cover the central openings in the jacket, the access openings for the magnetic heads and any other openings provided in the jacket. These envelopes are typically made of a special paper-like material which has the quality of reducing the likelihood of transferring dust from the envelope to the floppy diskette, such as the material marketed under the name "Tyvek" and sometimes of paper itself or other materials.
While the use of a jacket around the disk reduces to a great extent the contamination which finds its way to the magnetic information bearing surfaces of the floppy diskette, contamination still reaches the disk through the access openings and any other openings in the diskette jacket. The storing of the jacketed floppy diskette in an envelope when not in use helps alleviate the problem.
Unfortunately, for various reasons, floppy diskettes may not be immediately replaced in their envelopes after use. This may result from the envelope being temporarily misplaced or from user hurry or carelessness. The result is that the possibility of contamination of the floppy diskette surface is increased, with a consequent potential for impaired or reduced performance.
In view of the foregoing, it will be realized that it would be advantageous to include integral with a floppy diskette means to cover the openings in the jacket when the floppy diskette is not in use. Floppy diskettes of several sizes are in use. One size which presents constraints with respect to covering the openings in the jacket is the 51/4 inch floppy diskette which may have central openings in its jacket larger than 11/2 inches in diameter and small openings adjacent thereto for syncronization purposes on the order of 1/4 inch in diameter, in addition to the read-write access openings. In addition, severe constraints exist which limit the thickness of any means used to cover the openings in the jacket, since the floppy diskettes must often be inserted into narrow slots. These constraints exist especially along the edges and in the area of the read-write access openings.
The means for covering the openings in the jacket when the floppy diskette is not in use should be neither complex nor expensive, should not interfere with the operation of disk drives and should not require any modification to disk drives. Additionally, such means should be adaptable for use by users with their presently existing floppy diskettes and diskettes so adapted should be fully compatible and interchangeable with diskettes not so adapted.
No known device or system prior to the present invention has satisfied these coals.
U.S. Pat. No. 4,120,012 to Bowers describes a floppy diskette in which pivoting doors are provided within the jacket for covering the access openings. The pivoting doors require modification to the disk drive so that a tab or other part of the doors extending out beyond the edges of the floppy diskette jacket may be engaged when the floppy diskette is inserted into the disk drive or so a special pin within the disk-drive intrudes within the floppy diskette jacket.
This device does not cover the central opening of the floppy disk jacket; to do so in the case of the pivoting door described would require a greater range of angular rotation between the open and closed positions. This would necessitate further travel and greater lengths for the tabs or other parts which extend beyond the edges of the floppy diskette jacket or further intrusion into the diskette by the pin, than is taught by Bowers. It is not clear that a pin could practically intrude into the diskette far enough to rotate a door sufficiently to cover and uncover the central opening in the jacket as well as the read-write access openings without interfering with the disk itself.
In addition, these devices are not employable with already existing floppy diskettes, but would require special construction. In addition, the use of those devices all entail the inclusion of additional unsealed openings in the floppy disk jacket which, although small, nonetheless are undesirable.
Also described in Bowers is a sliding door mechanism located outside the floppy diskette. This embodiment keeps the door, as well as the tracks within which the door slides, in close proximity to the read-write access openings even while the door is open and the diskette is being used, enhancing the possibility of interference with the magnetic heads or associated apparatus in the disk drive. This device does not cover the central opening. It is not seen how any modification of the device could cover the openings in a typical 51/4" floppy diskette.